[libc] Extend MPFRMatcher to handle multiple-input-multiple-output functions.

Tests for frexp[f|l] now use the new capability. Not all input-output
combinations have been addressed by this change. Support for newer combinations
can be added in future as needed.

Reviewed By: lntue

Differential Revision: https://reviews.llvm.org/D86506

GitOrigin-RevId: 3f4674a5577dcc63a846d33f61e9bd95e388223d
6 files changed